*Article* **The Geometric Surface Structure of EN X153CrMoV12 Tool Steel after Finish Turning Using PCBN Cutting Tools**

**Michał Ociepa 1, Mariusz Jenek <sup>1</sup> and Piotr Kuryło 2,\***


**\*** Correspondence: P.Kurylo@ibem.uz.zgora.pl

**Abstract:** The article presents the results of studying the effects of coated (TiN, TiAlN) and uncoated polycrystalline cubic boron nitride (PCBN) machining blades on the key geometric structure parameters of the surface of hardened and tempered EN X153CrMoV12 steel after finish turning. A comparative analysis of the use of coated and coated cutting tools in finish turning of hardened steels was made. Tool materials based on polycrystalline cubic boron nitride PCBN (High-CBN; Low-CBN) have been described and characterized. The advantages of using TiN and TiAlN-coated cutting tools compared to uncoated were demonstrated. The lowest influence of the feed on the values of all tested roughness parameters was noted for surfaces treated with TiN- and TiAlN-coated tools (both with 50 vol.% of CBN). For uncoated tools (60 vol.% of CBN) for feeds *f* = 0.2 and 0.3 mm/rev., the highest values of *Ra* and *Rz* roughness parameters were found. Moreover, the lack of protective coating contributed to the occurrence of intense adhesive wear on the flank surface, which was also in the range of the feed values *f* = 0.2 and 0.3 mm/rev. The analysis of material surface after treatment with the uncoated tools with the feed *f* = 0.2 mm/rev. showed the occurrence of the phenomenon of lateral material flow and numerous chip deflections.

**Keywords:** roughness; coatings; finish turning; PCBN; tempered steel; tool wear
